Should the UN Genocide Convention be amended?

Two years ago a UN report on the situation in Darfur concluded against calling what was happening there a genocide, the investigating panel saying they had not found clear evidence of a policy - of a Sudanese government intent - to destroy a population group. In two posts at the time, and on the basis of what was being widely reported, I expressed some perplexity at this assessment. To a lay reader at any rate, without any expertise in the law, there seemed to be quite substantial indications of intent.

The issue is now raised again - not that it has ever really gone away in the meantime - by the outcome of a new UN enquiry:

UN investigators have accused Sudan's government of "orchestrating and participating" in crimes in Darfur that include murder, mass rape and kidnap.
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At least 200,000 people are estimated to have died in Darfur's four-year conflict, with millions more displaced.
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The five UN team members travelled to neighbouring Chad, to where many refugees have fled, and where the war itself is spreading.

There they heard reports backing up well-established accusations of serious abuses in Darfur, including mass rape, abduction, and forcing people from their homes.

"There are gross violations of human rights and international humanitarian law, the government is complicit in those crimes with the Janjaweed militia that it arms and trains," said the head of the mission, Nobel peace prize winner Jody Williams.

The Arab militia known as the Janjaweed have been accused of attacking villagers in Darfur, killing inhabitants and forcing others to flee, while the government provides air support.

The various elements reported here give rise to the same perplexity as before: 200,000 dead; many more displaced; gross violations of human rights, including murder, rape and driving people from their homes; all of it involving complicity, orchestration and participation of the Sudanese government. Read against Articles I and II of the UN Genocide Convention, it's hard to see what more is required to bring this within its terms.

However, a different thought now occurs to me. Article I reads as follows:

The Contracting Parties confirm that genocide, whether committed in time of peace or in time of war, is a crime under international law which they undertake to prevent and to punish.

Note the closing conjunction there: to prevent and to punish. It prompts the question whether prevention and punishment should be covered by the one definition of genocide. So far as punishment is concerned, the prosecution of individuals has to be governed by standards of proof of the most robust kind, and therefore intent must presumably be construed in the strictest way, as showing that those responsible at government level had a deliberate genocidal purpose, that precisely of 'destroy[ing], in whole or in part, a national, ethnical, racial or religious group, as such'. But if proof here - something that can be established only by a legal process, often long and drawn-out - is also made a condition of the prevention of genocide, then the definition of genocide is in danger of serving as a barrier to action, which it was surely not supposed to be. Even with all the 'material' elements of the crime apparently present, and some possibility (to put it no more strongly) of intent as well, the UN Convention cannot be held to apply without rigorous legal-type proof.

I put this forward tentatively, as I am not an international lawyer and there may be reasons which I'm unfamiliar with against separating the issues of prevention and punishment in the way I here suggest. But if so, it looks like bad news for peoples under organized, murderous attack.